[net-next-2.6.git] / arch / arm / mm / consistent.c

/*
 *  linux/arch/arm/mm/consistent.c
 *
 *  Copyright (C) 2000-2004 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  DMA uncached mapping support.
 */
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>

#include <asm/cacheflush.h>
#include <asm/io.h>
#include <asm/tlbflush.h>

#define CONSISTENT_BASE	(0xffc00000)
#define CONSISTENT_END	(0xffe00000)
#define CONSISTENT_OFFSET(x)	(((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)

/*
 * This is the page table (2MB) covering uncached, DMA consistent allocations
 */
static pte_t *consistent_pte;
static DEFINE_SPINLOCK(consistent_lock);

/*
 * VM region handling support.
 *
 * This should become something generic, handling VM region allocations for
 * vmalloc and similar (ioremap, module space, etc).
 *
 * I envisage vmalloc()'s supporting vm_struct becoming:
 *
 *  struct vm_struct {
 *    struct vm_region	region;
 *    unsigned long	flags;
 *    struct page	**pages;
 *    unsigned int	nr_pages;
 *    unsigned long	phys_addr;
 *  };
 *
 * get_vm_area() would then call vm_region_alloc with an appropriate
 * struct vm_region head (eg):
 *
 *  struct vm_region vmalloc_head = {
 *	.vm_list	= LIST_HEAD_INIT(vmalloc_head.vm_list),
 *	.vm_start	= VMALLOC_START,
 *	.vm_end		= VMALLOC_END,
 *  };
 *
 * However, vmalloc_head.vm_start is variable (typically, it is dependent on
 * the amount of RAM found at boot time.)  I would imagine that get_vm_area()
 * would have to initialise this each time prior to calling vm_region_alloc().
 */
struct vm_region {
	struct list_head	vm_list;
	unsigned long		vm_start;
	unsigned long		vm_end;
	struct page		*vm_pages;
};

static struct vm_region consistent_head = {
	.vm_list	= LIST_HEAD_INIT(consistent_head.vm_list),
	.vm_start	= CONSISTENT_BASE,
	.vm_end		= CONSISTENT_END,
};

static struct vm_region *
vm_region_alloc(struct vm_region *head, size_t size, int gfp)
{
	unsigned long addr = head->vm_start, end = head->vm_end - size;
	unsigned long flags;
	struct vm_region *c, *new;

	new = kmalloc(sizeof(struct vm_region), gfp);
	if (!new)
		goto out;

	spin_lock_irqsave(&consistent_lock, flags);

	list_for_each_entry(c, &head->vm_list, vm_list) {
		if ((addr + size) < addr)
			goto nospc;
		if ((addr + size) <= c->vm_start)
			goto found;
		addr = c->vm_end;
		if (addr > end)
			goto nospc;
	}

 found:
	/*
	 * Insert this entry _before_ the one we found.
	 */
	list_add_tail(&new->vm_list, &c->vm_list);
	new->vm_start = addr;
	new->vm_end = addr + size;

	spin_unlock_irqrestore(&consistent_lock, flags);
	return new;

 nospc:
	spin_unlock_irqrestore(&consistent_lock, flags);
	kfree(new);
 out:
	return NULL;
}

static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
{
	struct vm_region *c;
	
	list_for_each_entry(c, &head->vm_list, vm_list) {
		if (c->vm_start == addr)
			goto out;
	}
	c = NULL;
 out:
	return c;
}

#ifdef CONFIG_HUGETLB_PAGE
#error ARM Coherent DMA allocator does not (yet) support huge TLB
#endif

static void *
__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, int gfp,
	    pgprot_t prot)
{
	struct page *page;
	struct vm_region *c;
	unsigned long order;
	u64 mask = ISA_DMA_THRESHOLD, limit;

	if (!consistent_pte) {
		printk(KERN_ERR "%s: not initialised\n", __func__);
		dump_stack();
		return NULL;
	}

	if (dev) {
		mask = dev->coherent_dma_mask;

		/*
		 * Sanity check the DMA mask - it must be non-zero, and
		 * must be able to be satisfied by a DMA allocation.
		 */
		if (mask == 0) {
			dev_warn(dev, "coherent DMA mask is unset\n");
			goto no_page;
		}

		if ((~mask) & ISA_DMA_THRESHOLD) {
			dev_warn(dev, "coherent DMA mask %#llx is smaller "
				 "than system GFP_DMA mask %#llx\n",
				 mask, (unsigned long long)ISA_DMA_THRESHOLD);
			goto no_page;
		}
	}

	/*
	 * Sanity check the allocation size.
	 */
	size = PAGE_ALIGN(size);
	limit = (mask + 1) & ~mask;
	if ((limit && size >= limit) ||
	    size >= (CONSISTENT_END - CONSISTENT_BASE)) {
		printk(KERN_WARNING "coherent allocation too big "
		       "(requested %#x mask %#llx)\n", size, mask);
		goto no_page;
	}

	order = get_order(size);

	if (mask != 0xffffffff)
		gfp |= GFP_DMA;

	page = alloc_pages(gfp, order);
	if (!page)
		goto no_page;

	/*
	 * Invalidate any data that might be lurking in the
	 * kernel direct-mapped region for device DMA.
	 */
	{
		unsigned long kaddr = (unsigned long)page_address(page);
		memset(page_address(page), 0, size);
		dmac_flush_range(kaddr, kaddr + size);
	}

	/*
	 * Allocate a virtual address in the consistent mapping region.
	 */
	c = vm_region_alloc(&consistent_head, size,
			    gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
	if (c) {
		pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
		struct page *end = page + (1 << order);

		c->vm_pages = page;

		/*
		 * Set the "dma handle"
		 */
		*handle = page_to_dma(dev, page);

		do {
			BUG_ON(!pte_none(*pte));

			set_page_count(page, 1);
			/*
			 * x86 does not mark the pages reserved...
			 */
			SetPageReserved(page);
			set_pte(pte, mk_pte(page, prot));
			page++;
			pte++;
		} while (size -= PAGE_SIZE);

		/*
		 * Free the otherwise unused pages.
		 */
		while (page < end) {
			set_page_count(page, 1);
			__free_page(page);
			page++;
		}

		return (void *)c->vm_start;
	}

	if (page)
		__free_pages(page, order);
 no_page:
	*handle = ~0;
	return NULL;
}

/*
 * Allocate DMA-coherent memory space and return both the kernel remapped
 * virtual and bus address for that space.
 */
void *
dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
{
	return __dma_alloc(dev, size, handle, gfp,
			   pgprot_noncached(pgprot_kernel));
}
EXPORT_SYMBOL(dma_alloc_coherent);

/*
 * Allocate a writecombining region, in much the same way as
 * dma_alloc_coherent above.
 */
void *
dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
{
	return __dma_alloc(dev, size, handle, gfp,
			   pgprot_writecombine(pgprot_kernel));
}
EXPORT_SYMBOL(dma_alloc_writecombine);

static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
		    void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	unsigned long flags, user_size, kern_size;
	struct vm_region *c;
	int ret = -ENXIO;

	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

	spin_lock_irqsave(&consistent_lock, flags);
	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	spin_unlock_irqrestore(&consistent_lock, flags);

	if (c) {
		unsigned long off = vma->vm_pgoff;

		kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;

		if (off < kern_size &&
		    user_size <= (kern_size - off)) {
			vma->vm_flags |= VM_RESERVED;
			ret = remap_pfn_range(vma, vma->vm_start,
					      page_to_pfn(c->vm_pages) + off,
					      user_size << PAGE_SHIFT,
					      vma->vm_page_prot);
		}
	}

	return ret;
}

int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
		      void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
}
EXPORT_SYMBOL(dma_mmap_coherent);

int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
			  void *cpu_addr, dma_addr_t dma_addr, size_t size)
{
	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
}
EXPORT_SYMBOL(dma_mmap_writecombine);

/*
 * free a page as defined by the above mapping.
 */
void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
{
	struct vm_region *c;
	unsigned long flags, addr;
	pte_t *ptep;

	size = PAGE_ALIGN(size);

	spin_lock_irqsave(&consistent_lock, flags);

	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
	if (!c)
		goto no_area;

	if ((c->vm_end - c->vm_start) != size) {
		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
		       __func__, c->vm_end - c->vm_start, size);
		dump_stack();
		size = c->vm_end - c->vm_start;
	}

	ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
	addr = c->vm_start;
	do {
		pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
		unsigned long pfn;

		ptep++;
		addr += PAGE_SIZE;

		if (!pte_none(pte) && pte_present(pte)) {
			pfn = pte_pfn(pte);

			if (pfn_valid(pfn)) {
				struct page *page = pfn_to_page(pfn);

				/*
				 * x86 does not mark the pages reserved...
				 */
				ClearPageReserved(page);

				__free_page(page);
				continue;
			}
		}

		printk(KERN_CRIT "%s: bad page in kernel page table\n",
		       __func__);
	} while (size -= PAGE_SIZE);

	flush_tlb_kernel_range(c->vm_start, c->vm_end);

	list_del(&c->vm_list);

	spin_unlock_irqrestore(&consistent_lock, flags);

	kfree(c);
	return;

 no_area:
	spin_unlock_irqrestore(&consistent_lock, flags);
	printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
	       __func__, cpu_addr);
	dump_stack();
}
EXPORT_SYMBOL(dma_free_coherent);

/*
 * Initialise the consistent memory allocation.
 */
static int __init consistent_init(void)
{
	pgd_t *pgd;
	pmd_t *pmd;
	pte_t *pte;
	int ret = 0;

	spin_lock(&init_mm.page_table_lock);

	do {
		pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
		pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
		if (!pmd) {
			printk(KERN_ERR "%s: no pmd tables\n", __func__);
			ret = -ENOMEM;
			break;
		}
		WARN_ON(!pmd_none(*pmd));

		pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
		if (!pte) {
			printk(KERN_ERR "%s: no pte tables\n", __func__);
			ret = -ENOMEM;
			break;
		}

		consistent_pte = pte;
	} while (0);

	spin_unlock(&init_mm.page_table_lock);

	return ret;
}

core_initcall(consistent_init);

/*
 * Make an area consistent for devices.
 */
void consistent_sync(void *vaddr, size_t size, int direction)
{
	unsigned long start = (unsigned long)vaddr;
	unsigned long end   = start + size;

	switch (direction) {
	case DMA_FROM_DEVICE:		/* invalidate only */
		dmac_inv_range(start, end);
		break;
	case DMA_TO_DEVICE:		/* writeback only */
		dmac_clean_range(start, end);
		break;
	case DMA_BIDIRECTIONAL:		/* writeback and invalidate */
		dmac_flush_range(start, end);
		break;
	default:
		BUG();
	}
}
EXPORT_SYMBOL(consistent_sync);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/mm/consistent.c
	3	*
	4	* Copyright (C) 2000-2004 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* DMA uncached mapping support.
	11	*/
	12	#include <linux/module.h>
	13	#include <linux/mm.h>
	14	#include <linux/slab.h>
	15	#include <linux/errno.h>
	16	#include <linux/list.h>
	17	#include <linux/init.h>
	18	#include <linux/device.h>
	19	#include <linux/dma-mapping.h>
	20
	21	#include <asm/cacheflush.h>
	22	#include <asm/io.h>
	23	#include <asm/tlbflush.h>
	24
	25	#define CONSISTENT_BASE (0xffc00000)
	26	#define CONSISTENT_END (0xffe00000)
	27	#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
	28
	29	/*
	30	* This is the page table (2MB) covering uncached, DMA consistent allocations
	31	*/
	32	static pte_t *consistent_pte;
	33	static DEFINE_SPINLOCK(consistent_lock);
	34
	35	/*
	36	* VM region handling support.
	37	*
	38	* This should become something generic, handling VM region allocations for
	39	* vmalloc and similar (ioremap, module space, etc).
	40	*
	41	* I envisage vmalloc()'s supporting vm_struct becoming:
	42	*
	43	* struct vm_struct {
	44	* struct vm_region region;
	45	* unsigned long flags;
	46	* struct page **pages;
	47	* unsigned int nr_pages;
	48	* unsigned long phys_addr;
	49	* };
	50	*
	51	* get_vm_area() would then call vm_region_alloc with an appropriate
	52	* struct vm_region head (eg):
	53	*
	54	* struct vm_region vmalloc_head = {
	55	* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
	56	* .vm_start = VMALLOC_START,
	57	* .vm_end = VMALLOC_END,
	58	* };
	59	*
	60	* However, vmalloc_head.vm_start is variable (typically, it is dependent on
	61	* the amount of RAM found at boot time.) I would imagine that get_vm_area()
	62	* would have to initialise this each time prior to calling vm_region_alloc().
	63	*/
	64	struct vm_region {
65	struct list_head vm_list;
66	unsigned long vm_start;
67	unsigned long vm_end;
68	struct page *vm_pages;
69	};
70
71	static struct vm_region consistent_head = {
72	.vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
73	.vm_start = CONSISTENT_BASE,
74	.vm_end = CONSISTENT_END,
75	};
76
77	static struct vm_region *
78	vm_region_alloc(struct vm_region *head, size_t size, int gfp)
79	{
80	unsigned long addr = head->vm_start, end = head->vm_end - size;
81	unsigned long flags;
82	struct vm_region c, new;
83
84	new = kmalloc(sizeof(struct vm_region), gfp);
85	if (!new)
86	goto out;
87
88	spin_lock_irqsave(&consistent_lock, flags);
89
90	list_for_each_entry(c, &head->vm_list, vm_list) {
91	if ((addr + size) < addr)
92	goto nospc;
93	if ((addr + size) <= c->vm_start)
94	goto found;
95	addr = c->vm_end;
96	if (addr > end)
97	goto nospc;
98	}
99
100	found:
101	/*
102	* Insert this entry _before_ the one we found.
103	*/
104	list_add_tail(&new->vm_list, &c->vm_list);
105	new->vm_start = addr;
106	new->vm_end = addr + size;
107
108	spin_unlock_irqrestore(&consistent_lock, flags);
109	return new;
110
111	nospc:
112	spin_unlock_irqrestore(&consistent_lock, flags);
113	kfree(new);
114	out:
115	return NULL;
116	}
117
118	static struct vm_region vm_region_find(struct vm_region head, unsigned long addr)
119	{
120	struct vm_region *c;
121
122	list_for_each_entry(c, &head->vm_list, vm_list) {
123	if (c->vm_start == addr)
124	goto out;
125	}
126	c = NULL;
127	out:
128	return c;
129	}
130
131	#ifdef CONFIG_HUGETLB_PAGE
132	#error ARM Coherent DMA allocator does not (yet) support huge TLB
133	#endif
134
135	static void *
136	__dma_alloc(struct device dev, size_t size, dma_addr_t handle, int gfp,
137	pgprot_t prot)
138	{
139	struct page *page;
140	struct vm_region *c;
141	unsigned long order;
142	u64 mask = ISA_DMA_THRESHOLD, limit;
143
144	if (!consistent_pte) {
145	printk(KERN_ERR "%s: not initialised\n", __func__);
146	dump_stack();
147	return NULL;
148	}
149
150	if (dev) {
151	mask = dev->coherent_dma_mask;
152
153	/*
154	* Sanity check the DMA mask - it must be non-zero, and
155	* must be able to be satisfied by a DMA allocation.
156	*/
157	if (mask == 0) {
158	dev_warn(dev, "coherent DMA mask is unset\n");
159	goto no_page;
160	}
161
162	if ((~mask) & ISA_DMA_THRESHOLD) {
163	dev_warn(dev, "coherent DMA mask %#llx is smaller "
164	"than system GFP_DMA mask %#llx\n",
165	mask, (unsigned long long)ISA_DMA_THRESHOLD);
166	goto no_page;
167	}
168	}
169
170	/*
171	* Sanity check the allocation size.
172	*/
173	size = PAGE_ALIGN(size);
174	limit = (mask + 1) & ~mask;
175	if ((limit && size >= limit) \|\|
176	size >= (CONSISTENT_END - CONSISTENT_BASE)) {
177	printk(KERN_WARNING "coherent allocation too big "
178	"(requested %#x mask %#llx)\n", size, mask);
179	goto no_page;
180	}
181
182	order = get_order(size);
183
184	if (mask != 0xffffffff)
185	gfp \|= GFP_DMA;
186
187	page = alloc_pages(gfp, order);
188	if (!page)
189	goto no_page;
190
191	/*
192	* Invalidate any data that might be lurking in the
193	* kernel direct-mapped region for device DMA.
194	*/
195	{
196	unsigned long kaddr = (unsigned long)page_address(page);
197	memset(page_address(page), 0, size);
198	dmac_flush_range(kaddr, kaddr + size);
199	}
200
201	/*
202	* Allocate a virtual address in the consistent mapping region.
203	*/
204	c = vm_region_alloc(&consistent_head, size,
205	gfp & ~(__GFP_DMA \| __GFP_HIGHMEM));
206	if (c) {
207	pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
208	struct page *end = page + (1 << order);
209
210	c->vm_pages = page;
211
212	/*
213	* Set the "dma handle"
214	*/
215	*handle = page_to_dma(dev, page);
216
217	do {
218	BUG_ON(!pte_none(*pte));
219
220	set_page_count(page, 1);
221	/*
222	* x86 does not mark the pages reserved...
223	*/
224	SetPageReserved(page);
225	set_pte(pte, mk_pte(page, prot));
226	page++;
227	pte++;
228	} while (size -= PAGE_SIZE);
229
230	/*
231	* Free the otherwise unused pages.
232	*/
233	while (page < end) {
234	set_page_count(page, 1);
235	__free_page(page);
236	page++;
237	}
238
239	return (void *)c->vm_start;
240	}
241
242	if (page)
243	__free_pages(page, order);
244	no_page:
245	*handle = ~0;
246	return NULL;
247	}
248
249	/*
250	* Allocate DMA-coherent memory space and return both the kernel remapped
251	* virtual and bus address for that space.
252	*/
253	void *
254	dma_alloc_coherent(struct device dev, size_t size, dma_addr_t handle, int gfp)
255	{
256	return __dma_alloc(dev, size, handle, gfp,
257	pgprot_noncached(pgprot_kernel));
258	}
259	EXPORT_SYMBOL(dma_alloc_coherent);
260
261	/*
262	* Allocate a writecombining region, in much the same way as
263	* dma_alloc_coherent above.
264	*/
265	void *
266	dma_alloc_writecombine(struct device dev, size_t size, dma_addr_t handle, int gfp)
267	{
268	return __dma_alloc(dev, size, handle, gfp,
269	pgprot_writecombine(pgprot_kernel));
270	}
271	EXPORT_SYMBOL(dma_alloc_writecombine);
272
273	static int dma_mmap(struct device dev, struct vm_area_struct vma,
274	void *cpu_addr, dma_addr_t dma_addr, size_t size)
275	{
276	unsigned long flags, user_size, kern_size;
277	struct vm_region *c;
278	int ret = -ENXIO;
279
280	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
281
282	spin_lock_irqsave(&consistent_lock, flags);
283	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
284	spin_unlock_irqrestore(&consistent_lock, flags);
285
286	if (c) {
287	unsigned long off = vma->vm_pgoff;
288
289	kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
290
291	if (off < kern_size &&
292	user_size <= (kern_size - off)) {
293	vma->vm_flags \|= VM_RESERVED;
294	ret = remap_pfn_range(vma, vma->vm_start,
295	page_to_pfn(c->vm_pages) + off,
296	user_size << PAGE_SHIFT,
297	vma->vm_page_prot);
298	}
299	}
300
301	return ret;
302	}
303
304	int dma_mmap_coherent(struct device dev, struct vm_area_struct vma,
305	void *cpu_addr, dma_addr_t dma_addr, size_t size)
306	{
307	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
308	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
309	}
310	EXPORT_SYMBOL(dma_mmap_coherent);
311
312	int dma_mmap_writecombine(struct device dev, struct vm_area_struct vma,
313	void *cpu_addr, dma_addr_t dma_addr, size_t size)
314	{
315	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
316	return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
317	}
318	EXPORT_SYMBOL(dma_mmap_writecombine);
319
320	/*
321	* free a page as defined by the above mapping.
322	*/
323	void dma_free_coherent(struct device dev, size_t size, void cpu_addr, dma_addr_t handle)
324	{
325	struct vm_region *c;
326	unsigned long flags, addr;
327	pte_t *ptep;
328
329	size = PAGE_ALIGN(size);
330
331	spin_lock_irqsave(&consistent_lock, flags);
332
333	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
334	if (!c)
335	goto no_area;
336
337	if ((c->vm_end - c->vm_start) != size) {
338	printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
339	__func__, c->vm_end - c->vm_start, size);
340	dump_stack();
341	size = c->vm_end - c->vm_start;
342	}
343
344	ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
345	addr = c->vm_start;
346	do {
347	pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
348	unsigned long pfn;
349
350	ptep++;
351	addr += PAGE_SIZE;
352
353	if (!pte_none(pte) && pte_present(pte)) {
354	pfn = pte_pfn(pte);
355
356	if (pfn_valid(pfn)) {
357	struct page *page = pfn_to_page(pfn);
358
359	/*
360	* x86 does not mark the pages reserved...
361	*/
362	ClearPageReserved(page);
363
364	__free_page(page);
365	continue;
366	}
367	}
368
369	printk(KERN_CRIT "%s: bad page in kernel page table\n",
370	__func__);
371	} while (size -= PAGE_SIZE);
372
373	flush_tlb_kernel_range(c->vm_start, c->vm_end);
374
375	list_del(&c->vm_list);
376
377	spin_unlock_irqrestore(&consistent_lock, flags);
378
379	kfree(c);
380	return;
381
382	no_area:
383	spin_unlock_irqrestore(&consistent_lock, flags);
384	printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
385	__func__, cpu_addr);
386	dump_stack();
387	}
388	EXPORT_SYMBOL(dma_free_coherent);
389
390	/*
391	* Initialise the consistent memory allocation.
392	*/
393	static int __init consistent_init(void)
394	{
395	pgd_t *pgd;
396	pmd_t *pmd;
397	pte_t *pte;
398	int ret = 0;
399
400	spin_lock(&init_mm.page_table_lock);
401
402	do {
403	pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
404	pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
405	if (!pmd) {
406	printk(KERN_ERR "%s: no pmd tables\n", __func__);
407	ret = -ENOMEM;
408	break;
409	}
410	WARN_ON(!pmd_none(*pmd));
411
412	pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
413	if (!pte) {
414	printk(KERN_ERR "%s: no pte tables\n", __func__);
415	ret = -ENOMEM;
416	break;
417	}
418
419	consistent_pte = pte;
420	} while (0);
421
422	spin_unlock(&init_mm.page_table_lock);
423
424	return ret;
425	}
426
427	core_initcall(consistent_init);
428
429	/*
430	* Make an area consistent for devices.
431	*/
432	void consistent_sync(void *vaddr, size_t size, int direction)
433	{
434	unsigned long start = (unsigned long)vaddr;
435	unsigned long end = start + size;
436
437	switch (direction) {
438	case DMA_FROM_DEVICE: /* invalidate only */
439	dmac_inv_range(start, end);
440	break;
441	case DMA_TO_DEVICE: /* writeback only */
442	dmac_clean_range(start, end);
443	break;
444	case DMA_BIDIRECTIONAL: /* writeback and invalidate */
445	dmac_flush_range(start, end);
446	break;
447	default:
448	BUG();
449	}
450	}
451	EXPORT_SYMBOL(consistent_sync);